I backup my iMac several times a week.

I have the backups configured to ignore stuff in the cloud such as dropbox, OneDrive, Google Drive, the Photos system library, etc.

Most of the backups capture between one and two Gig and after de-duplication end up writing something between 300 to 700 MB to to the archive.

Today my backup captured 12.13 GB and wrote 5.26 GB to the archive after de-duplication and compression and I can't figure out why. This happens occasionally. I don't know what I did which would cause so many files to be captured as I don't recall doing anything on the iMac to do that.

So I'm really curious ? ? is there any way of looking at a specific layer/backup to see what files were captured, especially if there are any large ones?

Here's an abbreviated copy of the log entries from my last two backups ? ? the more "normal" one And the curiously large one.

Action 2019-06-18 12:06:48 ------- Capture to Backups.quanta
Action 2019-06-18 12:06:48 archive: /Volumes/Seagate/QRcall Archives ?/Backups.quanta
Action 2019-06-18 12:06:49 Capture Lion
Action 2019-06-18 12:06:49 Minutia Locating changes since Sunday, June 16, 2019 at 1:03 PM
Action 2019-06-18 12:10:57 Minutia Recaptured files
Action 2019-06-18 12:13:04 Excluded items
Action 2019-06-18 12:17:09 Ignored changes
Action 2019-06-18 12:20:18 Captured 2199 items, 1.46 GB (49% duplicate)
Action 2019-06-18 12:20:19 captured: 1.46 GB (1,460,142,366 bytes)
Action 2019-06-18 12:20:19 written: 377 MB (376,956,800 bytes)
Action 2019-06-18 12:20:19 duplicate: 719.9 MB (719,869,887 bytes) 49.30%
Action 2019-06-18 12:20:19 rate: 108.6 MB/min
Action 2019-06-18 12:20:19 files: 5,655
Action 2019-06-18 12:20:19 folders: 1,486
Action 2019-06-18 12:20:19 icons: 0
Action 2019-06-18 12:20:24 ------- Capture finished (13:35)

Action 2019-06-21 13:11:33 ------- Capture to Backups.quanta
Action 2019-06-21 13:11:33 archive: /Volumes/Seagate/QRcall Archives ?/Backups.quanta
Action 2019-06-21 13:11:34 Capture Lion
Action 2019-06-21 13:11:35 Minutia Previous layer had no bookmark; performing deep scan
Action 2019-06-21 13:55:49 Minutia Recaptured files
Action 2019-06-21 14:13:48 Excluded items
Action 2019-06-21 14:48:36 Captured 8245 items, 12.13 GB (45% duplicate)
Action 2019-06-21 14:48:36 captured: 12.13 GB (12,125,567,163 bytes)
Action 2019-06-21 14:48:36 written: 5.26 GB (5,258,723,768 bytes)
Action 2019-06-21 14:48:36 duplicate: 5.5 GB (5,502,469,402 bytes) 45.38%
Action 2019-06-21 14:48:36 rate: 125 MB/min
Action 2019-06-21 14:48:36 files: 28,306
Action 2019-06-21 14:48:36 folders: 5,375
Action 2019-06-21 14:48:36 icons: 0
Action 2019-06-21 14:48:43 ------- Capture finished (1:37:09)

Steven J Gold wrote: is there any way of looking at a specific layer/backup to see what files were captured, especially if there are any large ones?

Yes, there is.

Every layer is a delta, recording/adding only those changes that have occurred since the last layer.

Open the archive and drag the top and bottom layer shades to isolate a single layer. By hiding all of the changes that occurred before and after that layer, the item browser will show just those items that were captured in that layer. (If what you're looking for isn't obvious, use the View menu to show invisible items and package contents.)

You can also also use the shades to isolate a group of layers, showing you all of the items captured last week, for example.

Ah thanks, that's a start.

But why do almost all the items in the layer report a size (in sizes view) of "-1 bytes" and "Size undetermined" in the info panel?

When you use the top shade to hide earlier layers, the item browser can't use the pre-calculated size hints that are normally available to it.

To determine the size of a folder or package, the browser view must read all of the items it contains. Since this can, potentially, mean millions of items it doesn't do that automatically.

If you "drill down" into that folder, and every subfolder it contains, when you return back to the top level folder you'll see the calculated size. This is easiest to do in list view.

That makes sense. Thanks!